I’m so sorry that this happened to you. It’s more common than you think. He probably likes you just fine, but he (unlike you) just never had that deep, loving connection that you did. Right now, and as then, you were/are sort of his back up girl. He likes you, enjoyed having casual sex with you, but he never “fell in love” with you.
Unfortunately, there are a lot of guys who like to have more than one iron in the fire at any given time. That way he never has to be alone or have any downtime.
Most women (not all) have a very difficult time attempting to be “just friends” with someone that they have loved and lost. Because your relationship will never be what you wanted/expected it to be, and because he doesn’t feel the same way about you, it will always be a relationship that is on un-equal footing.
As hard as it will be to break away from him, completely, that is your best bet for getting over him. You will most likely always feel a twinge of love for him, but it’s better to put those feelings way in the back of your mind, so that you can move forward. If you attempt to be “just friends” with him, he will continue to tug at your heartstrings and give you mixed signals that are convenient for him. You’ll get tripped up and try to move into a real relationship with him again, and again he will rebuff you. Been there, done that.
I have to agree that it is in your best interest (his best interest doesn’t matter at this point, because you aren’t a couple) for you to break all contact with him. If you feel the urge to let him know that you will be breaking contact, just have a little chat or send him a note, that briefly tells him (without getting all emotional, because he will use that against you to either get you to change your mind, for his convenience, or to embarrass you, so that he looks like a super cool guy) that it is too painful for you to be “just friends” with him, because you feel more than that and you don’t want to be in an un-equal, un-rewarding situation with him. And then proceed to delete all of his contact info from your computer, phone, address book etc. If you have any gifts or mementos that he gave you, you have two fun choices. Either box the stuff up good and tight and put them in your attic or in the back of your closet, or have a nice little bonfire in your back yard. If you choose to keep the stuff, it can be comforting, knowing that the items meant something to you, and made you what you are today. But put them away. Just knowing that the stuff is there, can be enough to keep you from dragging it out and looking at it. I have a box like that. But burning the stuff can also be cathartic. Just depends on your own ideas of walking away from him.
Beyond that, don’t sit and wallow in your house. Have one good cry, with or without your good girlfriends, then say, “OK, now I’m done!” Then make plans to find out what kinds of activities you are going to involve yourself in from here on out. Make sure that you make yourself busy, doing fun things that you love, or doing nice things for other people that may need help (like doing volunteer work). Get up and get out of the house, every day. Do things. Don’t wallow. If you feel like you need to wallow, give yourself a 10 minute period each day, cry or scream if you have to, but after 10 minutes, STOP! Then go do something fun and constructive. After you start doing this every single day, the bad feelings of pain and remorse will lessen over time. Not immediately, but over time.
Next time that you meet someone that you are interested in, DO NOT compare them to the ex-boyfriend. That will stunt your growth and potential for finding love. But it’s OK to be upfront with any potential new guys and just let them know that you don’t want to get involved with some type of casual, wishy-washy situation, that you are interested in getting to know them and to see where it goes. But if the new guy doesn’t seem interested in persuing a real relationship (which is OK) then just casually dismiss yourself, early this time.
Good luck to you, my dear : )